The installation (physical) is straight forward. The "instructions" on the various looms and their connections are more problematic, particularly when coupled with accessories such as the OBDII, an external mic, the gps unit and a battery temp monitor. The diagram on the head unit is only good to help you sort out which plug (loom) plugs in where on the back of the head unit - there are lots of redundant wires and looms (well, for my installation).
The youtube video is slightly misleading on ...